1. Field of the Invention
The present invention relates to erectable metal shelving of the open-frame type.
2. Description of the Prior Art
Various types of open-frame shelving have heretofore been provided. These shelving arrangements may be of the four-post type with upright posts at the four corners of a rectangular configuration and shelves spanning the full area of the rectangular configuration and supported from the corner posts, either directly or via shelf supports. Six-post constructions include center posts at the opposite ends of the configuration, to permit effectively doubling the depth of the configuration from front to back.
One such prior system is marketed by the Barkley Division of Murray Envelope Corporation under the trademark SPACE PLUS. This double-depth arrangement may include double-depth shelves supported on horizontal shelf supports at the front and rear sides of the configuration, with the shelves being rigidified by center reinforcements which extend between the center posts and depend a substantial distance below the shelf, thereby impairing pass-through on the underlying shelf. Another version of this double-depth system utilizes single-depth shelves, each of which is supported between a shelf support at the outer side of the shelf and a backstop member at the inner side thereof. Such single-depth shelves at the front and rear sides of the configuration may be at staggered vertical levels or may be arranged at the same level. However, because they are supported by upstanding backstops at their inner sides, pass through from front to back is prohibited.
These two versions of this prior system have different center posts and do not permit both single-depth and double-depth shelves in the same system.